This invention relates to rotary displacement, or piston, pumps, and more particularly concerns fluid sealed rotary pumps adapted for producing high vacuums or moderate pressures. Although not so limited, the invention is particularly directed to guided vane type rotary displacement pumps having an eccentrically mounted stator; which pumps are especially useful for rapidly producing high vacuum or generating moderate pressures on the order of one atmosphere gauge.
Fluid sealed, rotary displacement, vacuum pumps, are widely used in laboratories and in industry for producing relatively high vacuum or generating moderate pressures. Customarily, they employ a rotary piston, or rotor, having a number of radially movable flat vanes, which rotor rotates within an eccentrically mounted stator. Centrifugal force tends to extend the vanes outwardly as the rotor rotates; the resulting volume change produced by stator extracts gases from a vacuum inlet and thereafter discharges the resulting compressed gases through a pressure outlet conduit. A nonreactive fluid, typically mineral oil, serves both to seal the pump components, to lubricate areas in frictional contact, and to reduce pump dead space.
Although widely used, rotary displacement vacuum pumps frequently suffer a number of disadvantages. Primarily, the pump designer is required to balance manufacturing simplicity, operational durability, and economy against high vacuum efficiency, not always with satisfactory results. Furthermore, even the best of rotary displacement pumps undergoes wear, usually at the vanes, and must be repaired or replaced with annoying frequency.
Accordingly, an object of the invention is to provide a durable, rugged, low cost, rotary displacement vacuum pump having an unusually high pumping speed. Still another object is to provide such pump having relatively few wearing parts, and including a means for rapidly removing and replacing as a unit all parts which are subject to wear. Yet another object is to provide a fluid sealed, rotary displacement, vacuum pump assembly in which the pumping components are contained within a single pump module, which may be renewed without careful alignment of parts, without undue down time, and without requiring a separate inventory of replacement parts.
Other and further objects, aims, and advantages of the invention will become apparent as the description thereof proceeds.